Topological Structures help?

I just received this poster via facebook and noticed it says rhino + grasshopper. Does anyone know or have a good idea of the process that goes into this kind of topological surface in just grasshopper(the one on the poster and others? I previously thought something of this sort would require maybe topmod, t-splines, scripting, or weaverbird, but it doesn't look like weaverbird. Just looking for suggestions on the topic thanks.